Andrew Hill created this mind-blowing map of the rivers of the continental United States, colored according to the direction in which they flow. Hill, of Vizzuality, used the the CartoDB platform and the National Hydrography Dataset, put out by the US Geological Survey, for this project. Is it geography or is it art? Eighteen colors are used on the map, representing points around the compass. At first glance, the veins on the map appear to blur together, or blend in some places. In order to best see the rivers’ directions, viewers need to zoom in and study the pinks, blues, greens, and reds. Hill claims the map was easy to make, but it’s worth hedging a bet that Einstein said the same thing about the theory of relativity once he’d gotten all the kinks sorted.
Via New Scientist
This image does not help you understand which way the water flows. The data may technically be there, but it is not visualised well. It would be easier to read if you just used a simple gradient from the start to the end of each river. You only need 2 colours, not 8.